The present invention relates to a conveying system comprising a drive chain and at least one conveying carrier.
The prior art discloses a number of conveying systems using a chain. As a rule, conveying means or carriers are fixedly mounted on the chain for carrying along the goods to be conveyed at least over a predetermined path. In most cases the goods are conveyed via transporting pins projecting at one side and having put thereover the goods which are normally in the form of hollow bodies. These systems have often the drawback that the chains must have a corresponding width for their conveying function.
It is thus the object of the present invention to provide a conveying system which can be used for conveying goods of the most different types.
To this end a conveying system is provided comprising a drive chain and at least one conveying carrier, the conveying chain comprising chain links which are arranged in a row and interconnected by a chain joint, a chain joint being formed by a sleeve pertaining to a first chain link and by a bolt passed through the sleeve and pertaining to a second chain link, the bolt projecting laterally at both sides and a transporting sleeve being arranged on each of the projecting end portions and the conveying carrier comprising an engaging means which can be brought into detachable engagement at least with both transporting sleeves of a bolt.
According to this design the conveying carrier itself thus comprises engaging means for the detachable engagement with transporting sleeves of a drive chain. A standard commercial chain may here be used that is equipped accordingly with bolts laterally projecting at both sides and with transporting sleeves arranged thereon. The use of such transporting sleeves makes it possible to protect the bolts from wear caused by engagement with the conveying carrier. The desired engagement characteristics can be obtained by selecting the most different materials. Moreover, the drive chain may be of a relatively small construction. Only the forces required for engagement with the engaging means must be transmitted. The conveying carriers can be adapted individually to the goods to be conveyed. That is why the conveying system is very flexible because the conveying track once provided by the drive chain can be used for the most different conveying goods. Suitable conveying carriers can be adapted to all imaginable conveying goods. Another advantage is that the drive chain could also be constructed in symmetry by the transporting sleeves arranged at both sides. The fact that two engagement points or portions are provided in spaced apart relationship for the engaging means on a bolt owing to the two transporting sleeves arranged thereon reduces wear and ensures a more stable and also less vibration-prone conveying function. In particular in the case of relatively large acceleration and deceleration operations this is of enormous advantage because a reliable engagement of the drive chain with the conveying carrier is ensured.
Advantageously, the transporting sleeves can be pressed onto the end portions of the bolts. Since there is no relative movement between bolt and transporting sleeve, all of the parameters to be provided for the wear characteristics with respect to the engagement with the conveying carrier must be satisfied by the transporting sleeve itself, so that an optimum adaptation can be chosen. Moreover, since the transporting sleeve is pressed onto the end portions of the bolts, the bolt need not be riveted so that other components, e.g. plates in the case of a possibly used plate chain, are secured. A riveting operation for deforming the end portions of the bolt is not needed. This function can be provided in an optimum way by suitably choosing the press fit between bolt and transporting sleeve.
Tests have shown that excellent transporting characteristics will be obtained according to one variant if a plastic material is used as the material for the transporting sleeve. Preferably, a polyamide (e.g. polyamide 12; lauramide or a polyacetal (ertacetal) can here be used. Apart from a noise reduction during the mostly sudden engagement between transporting sleeve and engaging means, suitable plastics also provide the necessary wear characteristics.
Preferably, the conveying carrier can comprise a toothing as the engaging means. Such a toothing may be in the manner of the toothing of a chain gear so that standard dimensions can be used in the chains.
In one embodiment, the conveying carrier is designed as a container and the toothing is molded onto the bottom side of the container. This has the advantage that a container can be used for an almost infinite number of different conveying goods and a corresponding receiving volume need only be provided with respect to the outer dimensions. For instance, standardized containers can here be used that are equipped with corresponding engaging means (toothing). Such a system would e.g. be excellently suited for a shelf system for a warehouse in which containers equipped with different goods must be transported to specific places, so that the containers are only in temporary engagement with the drive chain all the time.
Depending on the design of the engaging means it may entirely suffice when only every second bolt of the drive chain is provided with a transporting sleeve. Large gaps are thereby created between the transporting sleeves, the gaps permitting also a more stable design of the engaging means. In particular a toothing with broader or longer and thus more stable teeth could be designed.
Moreover, the drive chain can comprise alternating inner chain links and outer chain links, each inner chain link comprising two parallel sleeves and two parallel inner plates connecting the sleeves and each outer chain link comprising two parallel bolts and two parallel outer plates connecting the bolts, at least some bolts comprising end portions laterally projecting beyond the outer plates and having transporting sleeves arranged thereon. Consequently, use is made of a well known drive chain of a standard constructional type that comprises longer bolts with transporting sleeves only sporadically or exclusively. Such a drive chain is excellently suited for driving operations via a chain gear engaging into the gaps between the sleeves. Hence, the engagement of the engaging means of the conveying carrier is thus entirely decoupled from the engagement of a driving or deflecting chain gear.
To reduce wear by driving or deflecting chain gears, running sleeves may additionally be arranged in coaxial fashion on the sleeves.